Custom error, warning, and message functions.
pStop(..., who = -1L)pStop_(...)
pWarn(..., who = -1L)
pWarn_(...)
pMess(..., who = -1L)
pMess_(...)
message
integer or character.
If who is an integer, it is passed to sys.call to retrieve the name of the calling function.
One can also pass the name of the calling function in who.
In either case, the name of the calling function is included in the message.